This paper addresses issues on water resource vulnerability under climate change background. The concept and connotation of water resource vulnerability and the corresponding adaptive management are presented. The quantitative evaluation methods of water resource vulnerability, mainly include the index weight method, function and integrated indicator methods. The water resource vulnerability not only has natural variability but also is affected by changes in relationship between water supply and demand resulted from climate change and the impacts of droughts and floods. The key issue is to identify the governing variables which have main influence on water resource vulnerability. For future perspective, study on water resource vulnerability will go to adaptive management.

The probability change of extreme hydrological events under climate change is analyzed by constructing multi-variable model between climate factors and extreme events. Taiyuan meteorological station in the Yellow River basin and Lutaizi hydrological station in the Huaihe River basin are selected as study area. The results of Taiyuan station show that Gumbel Copula can better simulate the dependence structure of antecedent cumulated precipitation and monthly PDSI series. As the precipitation amount increases, the probability of extreme drought decreases while the probability of severe, moderate and slight drought firstly increases and then decreases. The results of Lutaizi station show that Clayton Copula can better simulate the dependence structure of precipitation and peak of flood. When the precipitation is over or equal to a certain value, the conditional probability of the extreme flood events that peak flow is over or equal to x gradually decreases as the annual maximum peak flow increases. Under the same conditional probability, the peak flow is more likely to get large values when the cumulative precipitation is large.

This study investigated the changes of extreme flood events with the long-term stream flow records of 1951-2010 at 23-typical cross-sections in the Pearl River basin. Flood magnitudes for return intervals larger than 10 years were defined as extreme flood events. Flood time series were derived from annual maximum (AM) series and peaks over threshold (POT) series respectively for 23 stream gauging stations in the main control sections. The Pearson type III distribution curve was selected for flood frequency analysis. Results indicate that the occurrence frequency of extreme flood events has increased after 1980s, specifically in recent two decades. Furthermore, the changes of extreme flood events were studied by comparing the flood frequency curves for the pre-1980 period (1951-1980) and post-1980 period (1981-2010). The flood extremes of 70% typical sections presented increasing tendencies in 1981-2010 compared with 1951-1980, with most of them in the Xijiang River basin, Beijiang River basin, and the western part of Guangdong Province. On the other hand, the rest 30 % sections, mainly concentrating in the Dongjiang River basin and the southern part of Guangxi Province, displayed decreasing tendencies.

The North China Plain (NCP) is an important region for food production, thus projection of changes in water cycle such as evaporation and runoff in the future are crucial to sustainable water resources utility and food security. Based on the integrated predictions of 23 climate models in the fourth assessment report of IPCC, annual evaporation and runoff were computed using the Schreiber-Thornthwaite method and then the spatio-temporal changes of air temperature, precipitation, evaporation and runoff were analyzed during 2001-2060 under the SRES A1B, A2 and B1 scenarios. The temperature will increase with higher rate in winter than summer season; whereas precipitation will increase with higher rate in summer than winter season. It is revealed that annual evaporation and runoff are acceleratively increasing and result in more spatial variability. Changes of evaporation and runoff can reach 7.1%-9.4% and 8.7%-10.7%, respectively in 2041-2060 relative to 1971-2000.

The regional climate model RegCM3 with the crop model CERES implemented was used to study the effects of crop growth and development on regional climate and hydrological processes over seven river basins of China. A 20-year numerical simulation shows that incorporating the crop growth and development processes improves simulated precipitation over Haihe River basin, Songhua River basin, and Pearl River basin; and compared with the control run RegCM3, the RegCM3_CERES reduces the negative biases of monthly mean 2-m air temperature over most river basins, especially over Haihe River basin and Huaihe River basin in summer. Maximum monthly evapotranspiration is found in summer (JJA) around 100 mm per month in the Yangtze River basin, Haihe River basin, Huaihe River basin and Pearl River basin. The seasonal and annual variations of water balance components (runoff, evapotranspiration, precipitation) over the seven river basins indicate that changes of evapotranspiration are in a good agreement with those of the total precipitation. Compared with the RegCM3, the RegCM3_CERES produces a reduced local water recycling rate over most river basins due to less evapotranspiration and more water flux into these basins; an increased precipitation in the Heihe River basin and Yellow River basin but to different extents a reduced precipitation in the rest river basins; a decline of summer leaf area index (1.20 m²/m²), an increase of root soil moisture (0.01 m³/m³), a decline of latent heat flux (1.34 W/m², but 16.00 W/m² in the Sichuan Basin), and an increase of sensible heat flux (2.04 W/m²) over the Yangtze River basin.

Regional climate model RegCM4 was used to investigate the regional climate effects of land cover change over China. Two 24-year (1978-2001) simulations, one with the land cover derived from the MODIS data and the other with the CLCV (Chinese land cover derived from vegetation map) data, were conducted for a domain encompassing China. The differences between the MODIS and CLCV data can basically reflect the characteristics of desertification and degradation of vegetation in China. Results indicate that the land cover change has important impacts on local climate through changes of surface energy and water budget and large-scale circulation. In summer, the land cover change leads to decrease in surface air temperature over southern China, reduction in precipitation and increase in surface air temperature in the monsoon marginal zone and the northern Tibetan Plateau, and increase in interannual variability of surface air temperature in the monsoon marginal zone and northwestern China. Strengthened southwesterly winds increase precipitation to some extent in central and eastern Inner Mongolia by enhancing water vapor transport. In winter, enhanced northerly winds bringing more dry and cold air lead to a precipitation reduction and a temperature decline over areas south of the Yellow River.

By using NCEP/NCAR monthly reanalysis dataset, Arctic Oscillation (AO) indices, the Northern Hemispheric (NH) and its four sectorial polar vortex (PV) area and intensity indices for the period 1951-2012, the relationships between PV, AO and the winter air temperature anomalies over NH continents, especially over Eurasian Continent were investigated. Results indicate that the correlation coefficients between AO index and the winter air temperature over NH showed a “-, +” pattern from the polar region to Eurasian Continent with the most significantly negative correlation center in the polar region and the significantly positive center in the Eurasian mid-high latitudes, but the correlation coefficients between NH’s polar vortex area indices and winter temperatures over NH exhibited a “+, -” pattern. In contrast to the AO index, the significant correlation area between Asian sector polar vortex area indices and winter temperatures expanded southeastward to eastern China, thus revealing some characteristics about the outbreak of the Asian winter monsoon from East Asian mid-high latitudes to the mid-low latitudes. The AO index has shown a decadal decreasing trend whereas both the NH’s and Asian sector polar vortex area indices have exhibited a decadal increasing trend since 2006, this decadal background provided the favorable conditions for the continuous anomalous low winter air temperature over the Eurasian Continent in recent years. The wide range of anomalous low winter air temperature during 2009-2011, was related to the enhancement of the negative phase of AO (except in 2011) and more closely related to the increase of NH’s and Asian sector polar vortex areas. This also indicates that the natural variability of winter cooling was obviously enhanced in Eurasian Continent.

This study examined surface air temperature trends over global land in 1901-2009 using data (monthly precipitation and monthly mean surface air temperature) from Climatic Research Unit (CRU) at University of East Anglia. It is found that the warming trend was particularly enhanced in the winter seasons over semi-arid regions at mid-high-latitude areas. By analyzing the temporal and spatial characteristics of dry/wet variation at the surface of North America and Eurasia and the impact of enhanced winter warming upon the dry/wet variation, it is found that the south of North America was becoming wet weakly and Arctic Archipelago in Canada became wet apparently while the middle and west of North America was drier. In Eurasia, most of the continent became drier, especially in the south of West Europe, North China, Northeast China, the central-north and northeast of Mongolia and far east of Russia. But there was no clear trend of precipitation in North America and Eurasia during the winter seasons in 1950-2008, so the dry/wet variation was mainly affected by the change of temperature, especially in the places where winter warming was enhanced.

This study analyzed tropospheric biennial oscillations (TBO) and abrupt changes of precipitation in the arid Central Asia (ACA) and their regional differences during 1930-2009 using the monthly 0.5°×0.5°gridded precipitation data from Climatic Research Unit (CRU) and the NCEP/NCAR monthly 2.5°×2.5° gridded geopotential height reanalysis data in 1948-2009. The results show that precipitation in ACA has significant TBO. The TBO of annual precipitation continued during 1930-2009 in subregions I (West Kazakhstan region), II (East Kazakhstan region) and IV (Kyrgyzstan region). However, there was an opposite trend in the intensity changes of TBO between sub-regions III (Central Asia Plains region) and V (Iran Plateau region) before and after the 1960s-1970s. The TBO of annual precipitation mainly resulted from winter precipitation in most of the sub-regions, except sub-region II where it mainly resulted from summer precipitation. Additionally, the temporally abrupt changes of precipitation were in good agreement with TBO signal changes in ACA, the periodicity of precipitation at abrupt change points all turned into TBO. From the perspective of the whole ACA region, abrupt change of precipitation occurred in western ACA in early 1950s, in eastern ACA in late 1960s and in Xinjiang in late 1980s, respectively. Although the precipitation’s TBO was observed in both the monsoon regions of East Asia and the arid Asian inland region where the westerlies dominated, the forcing factors might differ from each other. The quasi-biennial oscillation (QBO) of westerly wind circulation in the middle-upper troposphere might be one of the major factors that influence the TBO of precipitation in ACA.

The interannual variation of river runoff in the Songhua River and Liaohe River basins was analyzed using the 40-year (1961-2000) observed monthly precipitation data from 132 meteorological stations and the 45-year (1956-2000) monthly observed runoff data from Harbin, Jiangqiao and Tieling hydrometric stations. The annual runoff in the region showed a weak decreasing trend in the Songhua River catchment, and a significant decreasing trend in the Liaohe River catchment. The consistent periodic variations of high/low water were found between the two river catchments. In the earlier 1980s, an abrupt change in summer runoff was detected, that is, a distinctive declining trend starting from the mid-late 1960s changed into an increasing trend in the earlier 1980s. The relationship between summer runoff and precipitation was discussed, and it was found that precipitation is one of the important climatic factors governing the variation of observed river runoff. Our study also reveals the possible impacts of human activities and land cover changes on surface runoff.

This paper introduced the current status of the EU Emissions Trading Scheme (ETS), and summarized research findings about the impacts of the EU ETS on European power industry. It is concluded that the EU ETS would increase costs of power enterprises, raise electricity prices rapidly, increase profits of power enterprises greatly, and stimulate innovation of energy technologies. This paper also reviewed controversial issues caused by the EU ETS, such as the actual impact on power enterprises and power market, and the reason of windfall profits for power enterprises. On this basis, this paper compared the differences between China and EU, analyzed the impacts of domestic carbon emissions trading market on power industry, and put forward suggestions on establishing a China carbon emissions trading market.